I could have gone the WiFi way or the ethernet way.

I wanted to take the "secure" route first. WiFi might interfere with 868MHz radio, since there are big current spikes in WiFi chips which translate to voltage fluctuations and hence to radio emissions.

The other thing about WiFi is that it can be jammed more easily. A network cable is more robust and still can be 100 meters long. WiFi is much more limited in range.

And then there's user experience. With WiFi you might be more flexible in positioning the device but it can stop working from one day to the other and you'll never know why if you aren't an experienced user. This happened to me with a Raspberry Pi type computer. It was working for years and suddenly it would just lose the WiFi connection most of the time. It turned out that some new neighbour was transmitting on that very channel. A channel change on my side quickly fixed the problem. But you see: WiFi is not always "fire and forget".

Canique devices are meant to be fire-and-forget, though. This is why an old-fashioned RJ45 connection seemed wiser.